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�00 <br /> "TWINING <br /> CONCRETE INSIGHT <br /> Morrison Quarry Rock Petrography Page 42 <br /> 4.6 Rock Sample HDR-004 (66.4-67.0): Biotite Gneiss <br /> Received Condition <br /> The sample is a cored rock fragment that measures —60 mm (2 % in.) in diameter and <br /> —160-200 mm (6 1/4 - 7 7/8 in.) in length (Figure 4.6a). Both ends of the core are fractured <br /> surfaces and the side surfaces are rough cored surfaces. The core was received intact in one <br /> piece. No weathered surfaces are present. <br /> Polished Slab <br /> The rock on the polished surface is pale pink and bluish-gray to bluish-black (Munsell Soil <br /> Color 2.5YR 5-6/2 and GLEY 2 2.5-4/5PB) and predominantly consists of plagioclase <br /> feldspar, orthoclase feldspar, quartz, and biotite, with minor amounts of chlorite, and trace <br /> amounts of pyrite (Figure 4.6b, Figure 4.6c). The rock sample exhibits a well developed <br /> gneissose structure with alternating felsic (feldspar, quartz) and darker mineral layers (biotite, <br /> chlorite). Gneissic layers measure up to —16 mm (% in.) thick and are laterally discontinuous. <br /> Quartz and feldspar grains are medium to coarse grained and measure up to —25 mm (1 in.) <br /> in diameter. The rock sample exhibits a few randomly oriented quartz- and feldspar-rich <br /> veins. Pyrite is occasionally observed near quartz-rich areas. The rock sample is hard and <br /> competent and exhibits a Mohs hardness of 3.5-4+. <br /> Thin Section <br /> The rock is a high-grade metamorphic rock classified as a biotite gneiss (Figure 4.6d, <br /> Figure 4.6e). The sample consists of major amounts (>10%) of medium to coarse grained <br /> plagioclase feldspar, orthoclase feldspar, quartz measuring up to —25 mm (1 in.) in diameter, <br /> and fine to medium grained biotite measuring up to —2 mm (80 mil) in diameter. Minor <br /> amounts (1-10%) of chlorite is observed, and a trace amount (<1%) of opaque minerals is <br /> also observed. Quartz and felspar grains are subhedral to anhedral in shape and occur as <br /> segregated layers and as quartz and/or feldspar rich veins. Biotite and chlorite grains are <br /> elongated in shape and exhibit a preferred orientation. <br /> Sample HDR-004(66.4-67.0): Biotite Gneiss <br /> Major minerals Felspar 40-50% 30-40% ,biotite —20-30% <br /> (10-100%by volume of rock) p (� )'quartz(� ) ( ) <br /> Minor minerals Chlorite(-5-101/o) <br /> (1-10%by volume of rock) <br /> Trace minerals Pyrite,opaque minerals <br /> (<1%by volume of rock) <br /> Report No. 227893.d 22 November 2022 <br />